The iambic trimeter derives its name from its essential shape, which is three metrical units (hence trimeter) which are each basically iambic in form. The iambic metron has the following shape (where the x is an anceps, the - is a longum, and the u is a brevis):
Hence, reversing the current running though a wire will have the affect of reversing the direction of the magnetic force at a point some distance away from the wire. The affect that this has on the overall magnetic field depends on the shape of the wire.
Related to induction: induction heating, labor induction. induction. When a magnet is passed through a coil of wire, it produces an electric current. The direction of the flow of the current depends on the direction in which the magnet moves. In the top diagram the current flows from right to left. In the bottom diagram the current flows from left to right.